The major objectives of the proposed research project is to improve our understanding of the role of prostaglandins and their biosynthetic precursors and intermediates and consequences of inhibition of prostaglandin synthesis on vascular resistance and vasoconstrictor responses to sympathetic nerve stimulation, norepinephrine and angiotensin will be evaluated in this vascular bed. These studies will be carried out under conditions of controlled blood flow so that changes in vascular resistance will be directly reflected by changes in perfusion pressure. All data will be analyzed statistically and appropriate control experiments will be performed routinely to ensure that changes observed are not due to the passage of time or drug vehicles. Prostaglandins and/or their precursors may serve as modulators of adrenergic neurotransmission and thus the regulation of peripheral vasomotor tone. This project has great significance since prostaglandins and/or their precursors may play a role in the pathogenesis of conditions such as essential hypertension; a condition in which sympathetic vasoconstrictor tone or vascular responsiveness may be altered.